trans-Neptunian object

or trans·nep·tu·ni·an ob·ject

[ trans-nep-too-nee-uhn ob-jikt, ‐jekt, ‐tyoo‐, tranz ]

  1. any celestial object in our solar system whose orbit lies beyond Neptune, including Pluto: there may be some 70,000 trans-Neptunian objects orbiting 30–50 astronomical units from the sun, with diameters of at least 62 miles (100 km). Abbreviation: TNO

Origin of trans-Neptunian object

First recorded in 1920–25

Words Nearby trans-Neptunian object Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

Scientific definitions for trans-Neptunian object

trans-Neptunian object

[ trăns′nĕp-tōōnē-ən ]

  1. A celestial object that orbits the sun at a greater distance on average than Neptune.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.